Logical Reasoning

PT18 · S2 · Q6 A study was designed to establish

A free, expert breakdown of this official LSAT Logical Reasoning question.

  • Save & drill this skill — build targeted practice sets from questions like this one

  • Video walkthroughs — watch every question solved step by step

  • 81 official LSATs — as questions, timed sections & full-length tests

Start practicing free

A study was designed to establish what effect, if any, the long-term operation of offshore oil rigs had on animal life on the bottom of the sea.

Conclusion

Oil rigs have had no adverse effect on sea-bottom animals.

Evidence

The sea-bottom communities near the rigs were pretty similar to sea-bottom communities in control sites several miles from any rig.

Evaluate

This is an Anti-Causal argument, where the author takes the existence of sameness as an indication that one thing made no difference on another.

Our typical Anti-Causal objections are things like - would things have been even worse/better without this thing? - are the two things being compared really fair to compare?

In this example, we're thinking

Given That sea-bottom communities near rigs are similar to sea-bottom communities at control sites How Could We Argue That oil rigs are adversely affecting sea-bottom communities?

Goal

Look for an answer that would allow us to argue that oil rigs are adversely affecting sea-bottom communities (maybe we could say that the sea-bottom communities near the rigs used to be very different from the ones at control sites, prior to the arrival of the oil rigs)

6.

Which one of the following, if true, most seriously weakens the researchers’ conclusion?

  1. Commercially important fish depend on

    No Impact

    This tells us about a possible metric for measuring damage to sea-bottom communities, but we don't have any data about whether there has been any drop in catches of certain fish, so we have no way to use this metric to judge the current situation near oil rigs.

    6% picked this

  2. Correct

    The discharge of oil from

    Why this is right

    This hurts the argument by telling us that the study was looking in the wrong place. If we're trying to judge the impact of oil rigs, we shouldn't be looking near the rigs as the study did. We should be looking at considerable distance from the rig, because that's where the discharge would settle and so that's where the potential damage would occur. This answer doesn't offer any positive evidence that damage is occurring, but it weakens the argument by saying that the evidence presented is pretty much irrelevant to the conclusion being drawn.

    Skill tested: Weaken · how this choice captures the argument's function is the move to repeat next time.

    73% picked this

  3. Contamination of the ocean floor

    No Impact

    If the premise had said something like, "There are still plenty of animals near the rigs, so there wasn't any adverse affect", then maybe we could weaken by saying, "Yo, you can't just measure whether there are plenty of animals. We're not saying adverse effects would look like a total lack of animals. It would look like less species diversity and less density of life." But the premise was just saying "the community near the rigs (in terms of number, diversity, density) looked very similar to the community near the control sites".

    18% picked this

  4. Only part of any oil

    Strengthens, if Anything

    This is a pretty weak, wishy-washy idea. But if anything it is minimizing the potential risk of oil discharge to sea-bottom communities by saying that some of the discharge never reaches the ocean floor.

    2% picked this

  5. Where the ocean floor consists

    Irrelevant Distinction

    We have no idea if the ocean floor near the rigs or near the control sites has soft vs. rocky sediment, so even if this distinction were interesting to us, we have no way to apply it to the situation at hand.

    1% picked this

Continue the review in LSAT Lab

Save this question, watch the video walkthrough, and drill similar questions in your LSAT Lab account.

Save and practice this skill
LSAT Lab

Turn this review into a targeted study plan.

Save this question, drill more like it, watch the video walkthrough, and track your progress in your LSAT Lab account.

Start practicing free